Surgical fastening apparatus

ABSTRACT

A surgical fastening apparatus includes a fastener retaining frame having a first annular portion having a plurality of retainers circumferentially disposed thereon and a second annular portion having a plurality of circumferentially arranged perforations. The fastener retaining frame is detachably secured to a supporting structure. After the plurality of surgical fasteners has been mated with the plurality of retainers, an annular blade severs the perforations.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/787,368 filed Mar. 6, 2013, now U.S. Pat. No. 9,408,603, which is acontinuation of U.S. patent application Ser. No. 12/899,617 filed Oct.7, 2010, now U.S. Pat. No. 8,413,872, which claims benefit of andpriority to U.S. Provisional Application No. 61/326,292 filed Apr. 21,2010, which claims benefit of and priority to U.S. ProvisionalApplication No. 61/255,529 filed Oct. 28, 2009, and the disclosures ofeach of the above-identified applications are hereby incorporated byreference in their entirety.

BACKGROUND

Technical Field

The present disclosure relates to a surgical fastening apparatus and,more particularly, to a surgical fastening apparatus having a fastenerand retainer system.

Background of the Related Art

Various types of surgical stapling instruments for performing a circularanastomosis are well known, wherein an operator actuates the apparatusat a location which is relatively remote from the location at which thecircular anastomosis takes place. Anastomosis is the surgical joining ofseparate hollow organ sections. Typically, an anastomosis procedureinvolves surgery in which a diseased or defective section of hollowtissue is removed.

A conventional surgical stapling instrument for performing a circularanastomosis in a hemorrhoidal or other surgical procedure generallyincludes a shell assembly having an annular array of staples and stapleslots and an anvil assembly having a circular array of staple formingpockets in a proximal surface thereof. An example of surgical staplinginstruments for performing circular anastomosis is described in U.S.Pat. Nos. 7,168,604, 7,303,106 and pending U.S. application Ser. No.12/550,443, filed Aug. 31, 2009, all which are incorporated herein intheir entirety by reference. Typically, the anvil assembly islongitudinally movable from an open position to a closed position whichplaces the anvil assembly adjacent to the shell assembly to clamp thebody tissue therebetween. After bringing the anvil and shell assembliesto a closed position to clamp tissue, an annular pusher including aplurality of pushers which are configured to eject a correspondingstaple from the staple slot through the tissues and against a receivingpocket of the anvil to form staples is actuated by the operator in arelatively remote region to perform a circular anastomosis. Afterstapling the tissues together, the tissue is severed by the annularblade and extracted.

Surgical fastening instruments applying two part surgical fasteners areknown. In these instruments, a plurality of retainers are supported inan anvil assembly and a plurality of fasteners are supported in afastener holding assembly. The fasteners are advanced through tissue andinto engagement with openings in respective retainers. These two partfasteners are typically composed of resorbable material. The firingforce of the fasteners in some of these instruments could shift theretainers out of position which may result in misalignment. In addition,the retainers may slip against the anvil and/or may come off the anvilbefore firing which may also result in misalignment. Accordingly, itwould be advantageous to provide a configuration which enhances matingof the fasteners and the retainers and it may be useful to provide suchconfiguration in a circular anastomosis instrument.

SUMMARY

In accordance with the present disclosure, a surgical fasteningapparatus includes in one aspect a fastener retaining frame whichincludes a first annular portion having a plurality of retainersdisposed thereon and a second annular portion having a plurality ofperforations formed therein. A fastener guide member contains aplurality of surgical fasteners mateable with the plurality of retainersto fasten tissue therebetween. The fastener retaining frame isdetachably secured to a frame supporting structure. An annular pusherejects the plurality of surgical fasteners from the fastener guidemember towards the plurality of corresponding retainers. An annularblade severs the plurality of perforations after the plurality ofsurgical fasteners have been mated with the plurality of retainers.

In one embodiment, the surgical fastening apparatus further includes aflange member for detachably securing the fastener retaining frame,wherein the flange member is fixedly attached to an anvil. The secondannular portion defining the plurality of perforations may beconcentrically arranged within the first annular portion having theplurality of retainers circumferentially disposed thereon. In anembodiment, the first annular portion has a plurality of linksconnecting the plurality of retainers circumferentially disposed thereonforming a single body of retainers. In an alternative embodiment, theplurality of retainers are monolithically formed. In one embodiment, thefirst annular portion is monolithically formed with the second annularportion. The plurality of retainers circumferentially disposed on thefirst annular portion of the fastener retaining frame may be arranged todefine two concentric rings of retainers.

In one embodiment, the plurality of retainers are substantiallyuniformly spaced apart. In another embodiment, the plurality ofcircumferentially disposed perforations on the second annular portionare substantially uniformly spaced apart. The retainers may be made ofbiodegradable polymer. The plurality of surgical fasteners may also bemade of biodegradable polymer. The fastener retaining frame may be madeof biodegradable polymer.

In one embodiment, the flange member defines an annular recess todispose therein the fastener retaining frame, wherein the flange membercan include a ledge to securely dispose the fastener retaining frame inthe annular recess thereof. A distal side of the fastener retainingframe may be axially tapered with respect to the thickness thereof. Theannular recess defined by flange member may also be axially tapered withrespect to the thickness thereof corresponding to the axially taperedfastener retaining frame. The fastener retaining frame in someembodiments has a snap-fit configuration with the flange member.

In one embodiment, each of the plurality of perforations defined in thesecond annular portion has a radially notched portion configured tofacilitate breaking off thereof upon actuation of the annular blade. Inanother embodiment, each of the plurality of perforations defined in thesecond annular portion has a pair of opposing slits configured tofacilitate breaking off thereof upon actuation of the annular blade. Inone embodiment, the plurality of surgical fasteners are configured tosnap-fit with the plurality of retainers. In some embodiments, thethickness of a part defining the plurality of perforations in the secondannular portion of the fastener retaining frame is less than that of therest of the second annular portion to facilitate breaking off of theplurality of perforations. In some embodiments, the fastener retainingframe may be elastic. In some embodiments, the fastener guide member mayinclude a plurality of fastener slots axially extending andcircumferentially arranged for accommodating therein the plurality ofsurgical fasteners.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects and features of the present disclosure willbecome apparent from the following description of embodiments given inconjunction with the accompanying drawings, in which:

FIG. 1 is a front perspective view of an end effector in accordance withan embodiment of the present disclosure;

FIG. 2 is a rear perspective view of the end effector of FIG. 1;

FIG. 3 is an exploded perspective view of the end effector shown in FIG.1;

FIG. 4 is a partial cross-sectional perspective view of the distal endof the end effector of FIG. 1;

FIG. 5 is a perspective view of a fastener retaining frame and aplurality of fasteners prior to engagement;

FIG. 6 is an enlarged view of detail area “A” of FIG. 5; and

FIG. 7 is a perspective view of a surgical fastening apparatus includingthe end effector of FIG. 1 in accordance with an embodiment of thepresent disclosure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Various embodiments of the presently disclosed end effector will now bedescribed in detail with reference to the drawings, wherein likereferences numerals identify similar or identical elements. In thedrawings and in the description which follows, the term “proximal” willrefer to the end of the component that is closer to the operator duringuse, while the term “distal” will refer to the end of the component thatis farther from the operator, as is traditional and conventional in theart.

With reference to FIGS. 1, 2 and 7, an end effector 100 suitable for asurgical fastening apparatus 1000 is illustrated. A suitable example ofa surgical fastening apparatus 1000 is disclosed in U.S. Pat. Nos.7,168,604, 7,303,106 and U.S. application Ser. No. 12/550,443, filedAug. 31, 2009. The entire contents of each of these patents/applicationare incorporated by reference herein. The surgical fastening apparatus1000 includes a handle assembly 200, an elongate shaft 300 extendingdistally therefrom, and an end effector 100 coupled to the distal end ofthe elongate shaft 300. The length and the curvature of elongate shaft300 may be tailored to meet the specific needs of surgical procedurebeing performed. Elongate shaft 300 alternatively may be flexible tofacilitate maneuvering of surgical fastening apparatus 1000, morespecifically, end effector 100, to the targeted area in the bodycontaining tissues to be joined.

The handle assembly 200 generally includes a stationary handle 240, apivotable trigger 210 and a rotatable knob 220. When rotatable knob 220is manually rotated, anvil assembly 20 will longitudinally translate inrelation to shell assembly 10 between an open position and a closedposition in a manner to be described below. Actuation of trigger 210towards stationary handle 240 advances annular pusher 40 (FIG. 3)distally within shell assembly 10 to eject fasteners from shell assembly10 in a manner described below. Actuation of trigger 210 alsolongitudinally translates a circular knife 51 that severs tissue as wellas separates the formed fasteners from a retaining frame in a mannerdescribed below.

Referring now to FIGS. 3, and 5 an embodiment of the present disclosureis shown generally as staple end effector 100 defining a longitudinalaxis “A-A.” Staple end effector 100 includes an anvil assembly 20 and ashell assembly 10. Anvil assembly 20 includes an anvil 22, fastenerretaining frame 24, and a flange member 16. Flange member 16 ispreferably composed of plastic material such as HDPE. As will bediscussed in further detail below, fastener retaining frame 24 includesa plurality of perforations 26 and a plurality of retainers 28 (FIG. 5)and is detachably secured to flange member 16 which is fixedly attachedto anvil 22. Shell assembly 10 accommodates therein a fastener guidemember 30 which includes a plurality of axially extending andcircumferentially arranged fastener slots 34 for receiving therein aplurality of axially extending surgical fasteners 32 having distallydirected tissue piercing prongs for mating with the plurality ofretainers 28 on fastener retaining frame 24 to fasten tissuetherebetween. Shell assembly 10 further accommodates therein an annularpusher 40 including a plurality of pusher fingers 42 operably associatedwith the plurality of surgical fasteners 32. Each pusher 42 isconfigured for ejecting an associated surgical fastener 32 towards acorresponding retainer 28 on fastener retaining frame 24. A distal endof drive shaft 4 is operably connected with annular pusher 40 and aproximal end of drive shaft 4 is operably connected with trigger 210,whereby the actuation of trigger 210 distally advances drive shaft 4which advances annular pusher 40 within housing 45 of shell assembly 10to eject surgical fasteners 32 from fastener guide member 30 in a mannerto be described below. A circular knife 51 with an annular cutting bladeis advanced by pusher 40 to sever tissue in the manner described below.

With particular reference to FIGS. 5 and 6, fastener retaining frame 24will be described in detail. Fastener retaining frame 24 includes afirst annular portion 24 a having a plurality of retainers 28circumferentially disposed thereon and a second annular portion 24 bhaving a plurality of circumferentially arranged perforations 26. Thetwo annular portions 24 a and 24 b are concentrically arranged, with thesecond annular portion 24 b concentrically arranged within (radiallyinward of) the first annular portion 24 a. The plurality of retainers 28are either monolithically formed or are individually formed andconnected by suitable structures, e.g., links, thereby forming a singlebody. Moreover, first annular portion 24 a may be monolithically formedwith second annular portion 24 b. The first annular portion 24 a and thesecond annular portion 24 b may be made of different materials; in someembodiments they are made of biodegradable polymers (e.g. L4). Forclarity, only a few of the retainers, perforations, etc. are labeled.

With reference still to FIGS. 5, and 6 each retainer 28 includes abridge 27 and a pair of posts 29 each forming a cavity or opening 29 atherein (note for clarity only one of the retainers is labeled in FIG.5). Each retainer 28 is mated with an associated surgical fastener 32.Specifically, each prong 33 of the associated surgical fastener 32 isinserted into each cavity 29 a of an associated retainer 28. Surgicalfastener 32 and retainer 28 may be configured to engage in a snap-fitmanner. Furthermore, a tip 33 a of each prong 33 may include a barb 34to enhance secure mating with retainer 28. Bridge or backspan 35 extendsbetween prongs 33. The plurality of retainers 28 circumferentiallydisposed on first annular portion 24 a of fastener retaining frame 24are arranged to define a ring of retainers 28. The first annular portion24 a in the illustrated embodiment includes two rings of retainers 28wherein each ring has 16 retainers, although a different number ofretainers and/or a different number of rings is contemplated. When morethan one ring of retainers 29 is present in first annular portion 24 a,retainers 28 forming one ring may be radially aligned with those forminganother ring. Alternatively, retainers 28 forming one ring may have apartial overlap or be radially offset with those forming another ring asto allow uniform integrity of circular stapling. Retainers 28 may besubstantially uniformly spaced apart; however, the spacing betweenretainers 28 may be tailored to meet the specific needs of the surgicaloperation being performed. The fasteners 32 and retainers 28 arepreferably made of a resorbable material.

With reference still to FIG. 5, fastener retaining frame 24 includes aplurality of perforations 26 in second annular portion 24 b thereof. Theplurality of perforations 26 may be substantially uniformly formed(substantially uniformly spaced apart) in second annular portion 24 b.As an alternative to equidistant spacing or substantially equidistantspacing, other spacings for the perforations are also contemplatedincluding perforations arbitrarily defined or otherwise spaced. In oneembodiment, the plurality of perforations 26, like retainers 28, maydefine more than one ring of perforations. The diameter of each of theplurality of perforations 26 may be selected such that the thickness ofthe annular blade is less than the diameter of each of the perforations26. Such configuration may facilitate severing or breaking off of theplurality of perforations 26. In addition, each perforation 26 mayinclude a radially notched portion configured to facilitate severing orbreaking off of perforations 26 upon actuation of annular pusher 40.Alternatively, each perforation 26 may include a pair of opposing slitsalso serving to facilitate breaking off of perforations 26 uponactuation of annular pusher 40. When employing perforations 26containing for example the pair of slits, the width of the slits may bechosen to correspond with the thickness of the annular blade to allowthe annular blade to be engaged within the opposing slits of theassociated perforation. In some embodiments, the thickness of secondannular portion 24 b defining the plurality of perforations 26 may bevaried. For example, an inner part of the second annular portion 24 b,i.e., a part that is inside of the plurality of perforations 26, canhave a thickness less than that of an outer part of second annularportion 24 b, i.e., a part that is in contact with first annular portion24 a, whereby the relatively thinner part or a more brittle part canhave to facilitate breaking off of perforations 26 resulting in adetachment of fastener retaining frame 24 from flange member 16 as willbe discussed below. In the alternative, the thickness of only a partdefining the plurality of perforations 26 may be less than that of therest of second annular portion 24 b whereby such configuration alsofacilitates breaking off of the plurality of perforations 26 resultingin a detachment of fastener retaining frame 24 from flange member 16.

Turning back to FIG. 4, anvil assembly 20 in a closed position prior tothe firing of surgical fasteners 32 by the actuation of trigger 210 isillustrated. Flange member 16 has an annular recess 18 and includes aledge 18 a to form a supporting/retaining structure for the fastenerretaining frame 24. Fastener retaining frame 24 is disposed in annularrecess 18 and is secured therein by ledge 18 a. FIG. 4 illustrates ledge18 a securing fastener retaining frame 24 at second annular portion 24b. Accordingly, the thickness of the inner part of second annularportion 24 b and/or the rigidity of second annular portion 24 b may bechosen, e.g., by choosing the material having the requisite rigidity, toprevent bending of the mated fastener retaining frame 24 at perforations26 and/or at a location in contact with ledge 18 a prior to severing theplurality of perforations 26. In one embodiment, a distal side offastener retaining frame 24 is axially tapered with respect to thethickness thereof to enhance secure attachment thereof to annular recess18 of flange member 16 also axially tapered with respect to thethickness thereof. Flange member 16 having fastener retaining frame 24detachably secured thereto is fixedly attached to anvil 22 so thatfastener retaining frame 24 and anvil 22 move as a single unit in anlongitudinal translation thereof through a manual operation of therotational knob 220 by the operator.

Still referring to FIG. 4, shell assembly 10 accommodates fastener guidemember 30 which contains a plurality of circumferentially arranged andaxially extending fastener slots 34 for receiving therein a plurality ofaxially extending surgical fasteners 32 having tissue piercing prongs 33for mating with plurality of retainers 28 on fastener retaining frame 24to fasten body tissue therebetween. FIG. 4 illustrates a surgicalfastener 32 loaded in fastener slot 34 and having a proximal sidethereof engaged with an associated pusher 42 prior to being fired.

In use, anvil assembly 20 is spaced from shell assembly 10 as shown inFIG. 7 such that the end effector is an open or unapproximated position.Once the body tissues to be fastened are placed in the open spacebetween anvil assembly 20 and shell assembly 10, anvil assembly 20 istranslated proximally to an approximated position to clamp the bodytissues therebetween such that the end effector is in a closed orapproximated position. This is achieved by rotating the rotatable knob220 of the handle assembly 200.

As shown in FIG. 4, anvil assembly 20 in a pre-fired closed position isengaged with shell assembly 10 (see also FIG. 1).

The attachment of fastener retaining frame 24 to flange member 16, whichis fixedly attached to anvil 22, reduces slippage of fastener retainingframe 24 against anvil 22 and retains its position with respect to anvil22 during axial translations thereof. Once the clamping of the bodytissues has taken place, the operator actuates trigger 210 which in turndistally drives the drive shaft 4 connected to annular pusher 40. Theplurality of pushers 42 on the distally translated annular pusher 40ejects the corresponding set of surgical fasteners 32 from fastenerslots 34 of fastener guide member 30. Each of the ejected set ofsurgical fasteners 32 pierce through the body tissue and are receivedinto a corresponding retainer 28. Specifically, a portion of each of theprongs of fasteners 32 is received into a respective cavity 29 a formedin posts 29 in retainer 28. Note the tip 33 and barbs 34 of fastenerprongs 33 deform receiving walls 29 b of posts 29 as the fastener prong33 is forced through cavity 29 a. The barbs engage a ledge of the cavity29 a to prevent retraction (proximal movement) of the fastener 32,thereby locking the fastener 32 with the respective retainer 28. Notethat since fastener retaining frame 24 is securely attached to flangemember 16 which is fixedly attached to anvil 22, slippage of fastenerretaining frame 24 against anvil 22 due to the firing force produced bythe actuation of trigger 210 which ejects the plurality of fasteners 32from fastener slots 34 into the body tissues is reduced. Thus, theposition of fastener retaining frame 24 is maintained with respect toanvil 22 during the firing of surgical fasteners 32. Moreover, theplurality of retainers 28 are either monolithically formed orindividually formed and connected by suitable structures, e.g., links,thereby forming a single body. In either instance, the configuration ofthe plurality of retainers 28 as a single body, in conjunction withfastener retaining frame 24 being secured to flange member 16 which isfixedly attached to anvil 22, reduces the radial misalignment ofsurgical fasteners 32 with fastener retaining frame 24.

As noted above, fastener retaining frame 24 and fastener guide member 30may be configured to provide a plurality of rings of surgical fasteners32 on tissues, e.g., two rings of surgical fasteners wherein each ringis defined by sixteen fasteners, to meet the needs of the specificprocedure being performed. Upon mating of the plurality of surgicalfasteners 32 with fastener retaining frame 24, an annular blade 51 isactuated to distally translate through shell assembly 10. Note theannular blade can be translatable by actuation of the trigger 210 whichadvances the fasteners, or alternatively by a separate actuator actuatedin a separate step. The annular blade comes into contact with fastenerretaining frame 24 and is pressed against the plurality of perforations26 defined in the fastener retaining frame 24 severing or breakingperforations 26. The broken or severed perforations 26 enable the matedsurgical fastener 32 and fastener retaining frame 24 to be detached fromanvil 22. The severing or breaking off of perforations 26 leaves aresiduary ring, i.e., the inner part of second annular portion 24 b offastener retaining frame 24, within ledge 18 a of annular recess 18 offlange member 16. In some embodiments, in order to prevent perforationchips that may be produced during the severing or breaking off ofperforations 26, each of the plurality of perforations 26 may beprovided with, for example, a pair of opposing slits or a notchedportion, as mentioned above, wherein the thickness of the annular bladeis chosen to be smaller than, e.g., the width of the pair of opposingslits. The mated surgical fastener 32 and fastener retaining frame 24fastening body tissue therebetween would then be free to displacewithout being restricted or attached to anvil 22. Actuation of the knifesevers the tissue. The operator then moves anvil 22 to the open(unapproximated) position by rotating the rotatable knob 220 of thehandle assembly thereby distally translating anvil assembly 20. Afterthe removal of the severed tissue, e.g. hemorrhoidal tissue, thesurgical fastening device is removed from the body.

From the foregoing and with reference to the various figure drawings,those skilled in the art will appreciate that certain modifications canalso be made to the present disclosure without departing from the scopeof the same. For example, the annular blade may be fixedly secured tothe anvil and configured to break the plurality of perforations on thefastener retaining frame upon firing of the plurality of fasteners. Suchdesign eliminates the need for a longitudinal translation of the annularblade. Additionally, although disclosed as annular portions for use witha circular fastening apparatus, use of linear portions for use withapparatus applying linear arrays of fasteners are also contemplated.

While several embodiments of the disclosure have been shown in thedrawings and/or discussed herein, it is not intended that the disclosurebe limited thereto, as it is intended that the disclosure be as broad inscope as the art will allow and that the specification be read likewise.Therefore, the above description should not be construed as limiting,but merely as exemplifications of particular embodiments. Those skilledin the art will envision other modifications within the scope and spiritof the claims appended hereto.

What is claimed is:
 1. An end effector of a surgical instrumentcomprising: a tubular body including a plurality of surgical fastenerstherein; an anvil movable relative to the tubular body between open andapproximated positions; a fastener retaining frame including a pluralityof retainers configured to mate with the plurality of surgicalfasteners; and a flange secured with the anvil, the flange defining arecess configured to receive a portion of the fastener retaining frametherein, the flange including a ledge in registration with a part of thefastener retaining frame to secure the portion of the fastener retainingframe in the recess of the flange, wherein the portion of the fastenerretaining frame is severable, whereby the plurality of the retainers isdetachable from the anvil.
 2. The end effector of the surgicalinstrument according to claim 1, wherein the plurality of retainers iscircumferentially arranged on the fastener retaining frame.
 3. The endeffector of the surgical instrument according to claim 1, wherein theledge of the flange extends radially over the portion of the fastenerretaining frame to secure the portion of the fastener retaining framewithin the recess of the flange, such that when the portion of thefastener retaining frame is severed from the plurality of retainers, thepart of the fastener retaining frame is retained within the recess ofthe flange.
 4. The end effector of the surgical instrument according toclaim 1, wherein the portion of the fastener retaining frame includes aweakened portion.
 5. The end effector of the surgical instrumentaccording to claim 4, wherein the weakened portion is circumferentiallyarranged on the fastener retaining frame.
 6. The end effector of thesurgical instrument according to claim 4, wherein the weakened portionof the fastener retaining frame defines a plurality of perforations. 7.The end effector of the surgical instrument according to claim 1,wherein the fastener retaining frame includes a first annular portionincluding the portion of the fastener retaining frame received in therecess of the flange.
 8. The end effector of the surgical instrumentaccording to claim 7, wherein the fastener retaining frame furtherincludes a second annular portion including the plurality of retainers.9. The end effector of the surgical instrument according to claim 8,wherein the second annular portion is disposed about the first annularportion.
 10. The end effector of the surgical instrument according toclaim 8, wherein at least one of the first or second annular portions ismade of biodegradable polymers.
 11. The end effector of the surgicalinstrument according to claim 1, wherein the plurality of retainers ismonolithically formed.
 12. The end effector of the surgical instrumentaccording to claim 1, wherein the plurality of retainers is arranged todefine two concentric rings of retainers.
 13. The end effector of thesurgical instrument according to claim 12, wherein the two concentricrings of retainers are radially offset from each other.
 14. The endeffector of the surgical instrument according to claim 1, wherein eachretainer of the plurality of retainers defines a pair of cavitiesconfigured to receive prongs of the respective surgical fasteners. 15.The end effector of the surgical instrument according to claim 1,wherein the tubular body further includes an annular pusher for ejectingthe plurality of surgical fasteners toward the respective retainers. 16.The end effector of the surgical instrument according to claim 1,wherein the tubular body further includes an annular blade for severingthe portion of the fastener retaining frame to detach the plurality ofretainers from the anvil.
 17. The end effector of the surgicalinstrument according to claim 16, wherein a thickness of the annularblade of the tubular body is less than a diameter of each perforation ofa plurality of perforations defined in the portion of the fastenerretaining frame.
 18. The end effector of the surgical instrumentaccording to claim 1, wherein the fastener retaining frame is detachablysecured to the flange.
 19. An end effector of a surgical instrumentcomprising: a tubular body including a plurality of surgical fastenerstherein; an anvil movable relative to the tubular body to clamp tissuetherebetween; a fastener retaining frame including a plurality ofretainers configured to mate with the plurality of surgical fasteners ofthe tubular body; and a flange secured with the anvil, the flangedefining a recess configured to receive a portion of the fastenerretaining frame therein, the flange including a ledge extending radiallyover the portion of the fastener retaining frame to secure the portionof the fastener retaining frame within the recess of the flange, whereinthe portion of the fastener retaining frame is severable, such that theplurality of the retainers is detachable from the anvil.
 20. The endeffector of the surgical instrument according to claim 19, wherein theplurality of retainers is circumferentially arranged about the recess ofthe flange.
 21. The end effector of the surgical instrument according toclaim 19, wherein when the portion of the fastener retaining frame issevered from the plurality of retainers, a part of the fastenerretaining frame is retained within the recess of the flange.
 22. The endeffector of the surgical instrument according to claim 19, wherein theplurality of retainers is arranged circumferentially on the fastenerretaining frame to define two concentric rings of retainers.
 23. The endeffector of the surgical instrument according to claim 19, wherein thetubular body further includes an annular blade for severing the portionof the fastener retaining frame to detach the plurality of retainersfrom the anvil.